This invention relates to a dispensing valve of the automatically-sealing or self-closing type mounted on a cooperating spout of a flexible bag of a disposable bag-in-box package of the well-known type which is now commonly in use for packaging various liquids.
Various dispensing valves of this general type have been provided in the prior patent art as well as in actual use. One type of valve is illustrated in Fattori U.S. Pat. No. 3,400,866 and a further development thereof is illustrated in Scholle U.S. Pat. No. 3,443,728. Scholle U.S. Pat. No. 4,211,348 discloses a specifically different valve structure and discusses the two previously issued patents numbered above stating that the valves disclosed respectively therein suffer certain disadvantages in terms of sealing effectiveness and pressure capacity because the so-called Fattori valve seals on the lip of the spout which is often nicked or deformed. This Scholle U.S. Pat. No. 4,211,348 discloses a structure intended to overcome these disadvantages but which has other disadvantages.
Another prior art patent which was also discussed in Scholle U.S. Pat. No. 4,211,348 was the patent to Welsh, U.S. Pat. No. 3,972,452, as showing an axially inwardly extending flexible cylindrical wall or skirt which did seal on the interior surface of the spout but which Scholle contended used too much material and did not seal effectively.
The Scholle U.S. Pat. No. 4,211,348 states it overcomes the disadvantages of the prior art by providing a valve in the form of flat-bottom, cylindrical cup-shape flexible member which has a cylindrical wall that fits within the spout and stresses that it has an annular sealing bead on the outer surface thereof for sealing engagement with the spout axially inwardly from the lip thereof, a toggle lever being provided to bend the cylindrical wall and sealing bead radially-inwardly to provide a dispensing outlet between the wall and spout. The main disadvantage of this structure is that the relatively heavy sealing bead on the cylindrical wall must be flexed with the wall each time the valve is opened so that after repeated use it tends to become distorted. Also, the bead stiffens the wall so that more pressure on the toggle lever is required to flex it and flow is difficult to regulate because of the pressure required to hold the lever at various positions.